The present invention relates to fabricating an article having a toric-like aspheric figure. More particularly, the present invention is concerned with a method for use in fabricating an aspheric lens having a similar toric surface in which the sub-radius of the aspheric lens varies depending on the position.
As disclosed in Japanese Patent Unexamined Publication No. 62-203744, a typical known method for fabricating a toric lens employs a lapping tool having a configuration complementary to the configuration of the lens to be obtained. The lapping method is effected such that the lens is formed by lapping namely, by pressing the glass material to the rapping tool through the intermediary of a lapping powder supplied into the space between the lapping tool and the glass.
On the other hand, Japanese Patent Unexamined Publication No. 62-176747 discloses a method and an apparatus for processing a toric figuration by a combination of rotations about two axes.
The method disclosed in Japanese Patent Unexamined Publication No. 62-203744 only enables fabrication of a toric configuration which is shown by a broken line in FIG. 2. On the other hand, it has been known that, in some uses of aspheric lenses such as an optical component of a laser beam printer, the optical image property can significantly be improved by the use of a similar toric lens having a surface which is slightly deviated from a toric form. In this field of industry, therefore, there is a demand for an efficient method for fabricating a lens having a similar toric surface.